Embryology of Cymbidium sinense: Embryo development

Abstract

Embryo development in Cymbidium sinense is characterized by two consecutive oblique divisions resulting in the formation of a four- celled embryo. Three of the four cells towards the micropyle begin to vacuolate while the remaining cell located at the terminus remains cytoplasmic. The three cells towards the base become suspensor cells, and they continue to elongate and expand by the process of vacuolation. The terminal cytoplasmic cell continues to divide and give rise to the embryo proper and additional suspensor cells. Nile red staining indicates the absence of cuticular material in the walls of the suspensor cells. A positive reaction towards nile red can be detected in the embryo proper after periclinal divisions have ceased in the surface layer. In the mature embryo, storage protein and lipid are present in the cells of the embryo proper.